This invention relates to a fluorinated compound, 4,5-difluorophthaloyl fluoride, and to a method for the preparation thereof. 4,5-Difluorophthaloyl fluoride is useful as a chemical intermediate in the preparation of various chemical end products, such as 4,5-difluorophthalimide and resins such as polyamides, and the like. Polyamides having fluorine substituents on the polymer chain may be prepared by polycondensation of 4,5-difluorophthaloyl fluoride with a suitable diamine, such as piperazine, utilizing such known techniques as interfacial polymerization or solution polymerization.